When Linux 3.18-rc6 was released last Sunday, Linus Torvalds noted in the release announcement that a "a big unknown worry in a regression" remained. Nearly one week later, kernel developers are still figuring out what's going on with this regression that can cause frequent lockups. Worse off, it looks like it might affect the Linux 3.17 kernel too.

Earlier this week on Phoronix I posted benchmarks indicating potential block/file-system performance regressions using the Linux 3.18 kernel. Since then I've been carrying out more tests looking for any file-system performance problems on other hardware.

Of the RAID 0/1/5/6/1+0 levels supported natively by the Btrfs file-system, it's been the RAID 5 and RAID 6 implementations that have been deemed experimental and not yet production ready. Fortunately, that may soon be changing with some fresh Btrfs tool patches.

While Linus Torvalds was a bit unhappy about the continued flow of late changes for the Linux 3.18 kernel, with today's 3.18-rc4 release he's happy that the past week has indicated a slowdown in changes for Linux 3.18.

Besides Oracle, Facebook, and SUSE, another major company that's been investing in the Btrfs next-generation Linux file-system has been Fujitsu. Btrfs already offers some compelling, ZFS-like features not found in other native Linux file-systems while more work is still happening.

Back in February SUSE unveiled a new means of live Linux kernel patching, kGraft, compared to the existing Ksplice. One month later, Red Hat unveiled their own solution that happened to be under development at the same time, Kpatch. Since both of them have been out, both have pursued mainline interests but neither one accepted upstream yet. Now a new live kernel patching solution is out that tries to take the best of both worlds.

When Linux 3.18-rc1 was released last week, one week sooner than anticipated, Linus Torvalds mentioned he was willing to still allow OverlayFS to be merged this cycle. One week later, that code is hopefully now ready for merging.

With Linux 3.18-rc1 arriving one week early I didn't have a chance to write a feature overview of Linux 3.18 prior to this first development release that marked the close of the merge window. For those that didn't stay up to date with our dozens of Linux 3.18 kernel articles about changes and new features, here's a concise overview.